The Experts below are selected from a list of 327 Experts worldwide ranked by ideXlab platform
Jiyong Zhao - One of the best experts on this subject based on the ideXlab platform.
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High-Energy-resolution monochromator for 83Kr nuclear resonant scattering
Review of Scientific Instruments, 2002Co-Authors: Jiyong Zhao, Thomas S. Toellner, Wolfgang Sturhahn, Esen E. Alp, Guoyin Shen, Ho-kwang MaoAbstract:We have built a high-Energy-resolution monochromator for nuclear resonant scattering from the 9.4 keV nuclear transition of 83Kr. The monochromator consists of two highly asymmetric silicon single crystals arranged in a dispersive geometry and produces an Energy Bandwidth of 2.3 meV. This monochromator has been successfully used for a study of nuclear forward scattering and nuclear resonant inelastic scattering from a 83Kr sample that was solidified in a diamond anvil cell at 2.15 GPa and room temperature.
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crystal monochromator with a resolution beyond 108
Journal of Synchrotron Radiation, 2001Co-Authors: Thomas S. Toellner, W Sturhahn, G Bortel, E E Alp, Jiyong ZhaoAbstract:Monochromatization with crystal diffraction has been achieved to a resolution (/) beyond 108. The monchromator is specifically designed for 23.880 keV synchrotron radiation ( = 51.9 pm) for applications involving nuclear resonant scattering from 119Sn. The design uses asymmetrically cut silicon (12 12 12) crystal reflections from two single-crystalline monoliths oriented in a dispersive geometry. A transmitted Energy Bandwidth of 140 ± 20 µeV was measured, corresponding to a resolution of 1.7 × 108. Methods of improving efficiency, wavelength stability and resolution are discussed.
Thomas S. Toellner - One of the best experts on this subject based on the ideXlab platform.
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High-Energy-resolution monochromator for 83Kr nuclear resonant scattering
Review of Scientific Instruments, 2002Co-Authors: Jiyong Zhao, Thomas S. Toellner, Wolfgang Sturhahn, Esen E. Alp, Guoyin Shen, Ho-kwang MaoAbstract:We have built a high-Energy-resolution monochromator for nuclear resonant scattering from the 9.4 keV nuclear transition of 83Kr. The monochromator consists of two highly asymmetric silicon single crystals arranged in a dispersive geometry and produces an Energy Bandwidth of 2.3 meV. This monochromator has been successfully used for a study of nuclear forward scattering and nuclear resonant inelastic scattering from a 83Kr sample that was solidified in a diamond anvil cell at 2.15 GPa and room temperature.
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crystal monochromator with a resolution beyond 108
Journal of Synchrotron Radiation, 2001Co-Authors: Thomas S. Toellner, W Sturhahn, G Bortel, E E Alp, Jiyong ZhaoAbstract:Monochromatization with crystal diffraction has been achieved to a resolution (/) beyond 108. The monchromator is specifically designed for 23.880 keV synchrotron radiation ( = 51.9 pm) for applications involving nuclear resonant scattering from 119Sn. The design uses asymmetrically cut silicon (12 12 12) crystal reflections from two single-crystalline monoliths oriented in a dispersive geometry. A transmitted Energy Bandwidth of 140 ± 20 µeV was measured, corresponding to a resolution of 1.7 × 108. Methods of improving efficiency, wavelength stability and resolution are discussed.
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A high-resolution monochromator for inelastic nuclear resonant scattering experiments using
Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment, 1999Co-Authors: Thomas S. Toellner, Wolfgang Sturhahn, P.m. Hession, J.p. Sutter, Esen E. AlpAbstract:Abstract We report a silicon crystal monochromator with an angular acceptance of 14.1 μrad and an Energy Bandwidth of 3.6 meV at 23.880 keV X-ray Energy – an Energy resolution δE / E of 1.5×10 −7 . In combination with an undulator source, the monochromator is used to measure the partial phonon density of states of Sn in 119 SnO 2 by the method of inelastic nuclear resonant scattering using the 23.880 keV nuclear transition of 119 Sn .
Wayne E. Stark - One of the best experts on this subject based on the ideXlab platform.
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Energy-Bandwidth Efficiency Tradeoff in MIMO Multi-Hop Wireless Networks
IEEE Journal on Selected Areas in Communications, 2011Co-Authors: Chih-liang Chen, Wayne E. Stark, Sau-gee ChenAbstract:This paper considers a MIMO multi-hop network and analyzes the relationship between its Energy consumption and Bandwidth efficiency. Its minimum Energy consumption is formulated as an optimization problem. By taking both transmit antennas (TAs) and receive antennas (RAs) into consideration, the Energy-Bandwidth efficiency tradeoff in the networks is investigated. Moreover, the minimum Energy of an equally-spaced relaying strategy is investigated for various numbers of antennas. In addition, the minimum Energy over all possible antenna pairs is derived. Finally, the effect of the number of hops on the Energy-Bandwidth efficiency tradeoff is considered. For a fixed antenna pair, the minimum Energy over all possible rates and hop numbers are obtained. Generally, the routes with more hops minimize the Energy consumption in the low effective rate region. On the other hand, in the high effective rate region, the routes with fewer hops minimize the Energy consumption.
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Distance-aware transmission Energy selection for multi-hop wireless networks with spatial reuse
2010 - MILCOM 2010 MILITARY COMMUNICATIONS CONFERENCE, 2010Co-Authors: Changhun Bae, Wayne E. StarkAbstract:We consider the Energy-Bandwidth tradeoff in a 2-dimensional multi-hop wireless network with spatial reuse. Spatial reuse is introduced to improve the Bandwidth efficiency but also causes interference. In this paper, we propose a new transmission Energy selection strategy in interference-limited networks in order to improve network throughput. The proposed strategy is distance-aware transmission, where it takes into account both interfering distance (unwanted interference) and forwarding distance (wanted transmission). The Energy-Bandwidth tradeoff for this strategy is investigated. Both the Energy transmitted and the Energy used at the receiver are considered. Numerical results indicate a significant improvement compared to the uniform power transmission case.
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On the Energy-Bandwidth tradeoff for AWGN relay channels
MILCOM 2009 - 2009 IEEE Military Communications Conference, 2009Co-Authors: Changhun Bae, Wayne E. StarkAbstract:This paper investigates the Energy-Bandwidth trade-off of various relaying strategies over the AWGN channel. The total Energy consumption per information bit includes the receiver circuit processing Energy at the relay and destination as well as the transmitted Energy. With the cooperation of the source and relay, the end-to-end Bandwidth efficiency can be improved at the cost of receiver processing Energy. We consider both decode-and-forward and amplify-and-forward strategies. Energy-Bandwidth tradeoffs for the decode-and-forward and amplify-and-forward relaying strategies are compared. It is shown that for low rates, the case without cooperation outperforms the case with cooperation for both strategies. However when the Energy required for processing at the receiver is ignored, it is helpful to cooperate for the amplify-and-forward scheme while the result depends on the desired rate for the decode-and-forward scheme. It is also shown that the amplify-and-forward scheme does not achieve the minimum Energy per bit at low SNR due to its noise propagation characteristic. Bounds on the minimum total Energy consumption are derived and compared with the result without cooperation.
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End-to-End Energy–Bandwidth Tradeoff in Multihop Wireless Networks
IEEE Transactions on Information Theory, 2009Co-Authors: Changhun Bae, Wayne E. StarkAbstract:In this paper, Energy-constrained wireless multihop networks with a single source-destination pair are considered. A network model that incorporates both the Energy radiated by the transmitter and the Energy consumed by the circuits that process the received signals is proposed. The rate of communication is the number of information bits transmitted (end-to-end) per coded symbol transmitted by any node in the network that is forwarding the data. The tradeoff between the total Energy consumption and the end-to-end rate of communication is analyzed. The performance (either Energy or rate) depends on the transmission strategy of each node, the location of the relay nodes, and the data rate used by each node. Communication strategies include the rate of transmission on each link, the scheduling of links, and the power used for each link. Strategies that minimize the total Energy consumption for a given rate are found. Two communication strategies that capture the inherent constraints of some practical networks are also considered and compared with the optimum strategies. In the case of equispaced relays, analytical results for the tradeoff between the Energy and the end-to-end data rate are provided. The minimum Energy over all possible data rates is also obtained. Low rates incur a significant penalty because the receiver is on for a long time period while high rates require high transmission Energy. At high rates routes with fewer hops minimize the Energy consumption while at lower rates more hops minimize the Energy consumption.
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Energy-Bandwidth tradeoff with spatial reuse in wireless multi-hop networks
MILCOM 2008 - 2008 IEEE Military Communications Conference, 2008Co-Authors: Changhun Bae, Wayne E. StarkAbstract:In this paper, we investigate the Energy-Bandwidth tradeoff of wireless multi-hop networks with spatial reuse. For the end-to-end Bandwidth utilization, we consider the number of information bits transmitted (end-to-end) per coded symbol transmitted by any node in the network that is forwarding the data. The total Energy consumption per information bit by the network includes the Energy transmitted and the receiver processing Energy. Spatial reuse is considered to enhance the Bandwidth efficiency by allowing simultaneous transmission. Bounds on the Energy-Bandwidth tradeoff are derived from convex optimization problem. With receiver processing Energy, it is shown that spatial reuse degrades the Energy efficiency but improves the Bandwidth utilization. We demonstrate that this degraded total Energy consumption can be improved by varying the minimum separation of simultaneous transmitters.
S. Collins - One of the best experts on this subject based on the ideXlab platform.
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Hybrid diamond-silicon angular-dispersive x-ray monochromator with 0.25-meV Energy Bandwidth and high spectral efficiency
Optics express, 2013Co-Authors: Stanislav Stoupin, Yuri Shvyd'ko, Deming Shu, Vladimir Blank, Sergey Terentyev, Sergey N. Polyakov, M.s. Kuznetsov, Ivan Lemesh, Kiran Mundboth, S. CollinsAbstract:We report on the design, implementation, and performance of an x-ray monochromator with ultra-high Energy resolution (ΔE/E ≃ 2.7 × 10−8) and high spectral efficiency using x rays with photon energies E ≃ 9.13 keV. The operating principle of the monochromator is based on the phenomenon of angular dispersion in Bragg back-diffraction. The optical scheme of the monochromator is a modification of a scheme reported earlier [Shvyd’ko et al., Phys. Rev. A 84, 053823 (2011)], where a collimator/wavelength selector Si crystal was replaced with a 100-μm-thick type IIa diamond crystal. This modification provides a very-small-Energy Bandwidth ΔE ≃ 0.25 meV, a 3-fold increase in the aperture of the accepted beam, a reduction in the cumulative angular dispersion rate of x rays emanating from the monochromator for better focusing on a sample, a sufficient angular acceptance matching the angular divergence of an undulator source (≈ 10 μrad), and an improved throughput due to low x-ray absorption in the thin diamond crystal. The measured spectral efficiency of the monochromator was ≈ 65% with an aperture of 0.3 × 1 mm2. The performance parameters of the monochromator are suitable for inelastic x-ray spectroscopy with an absolute Energy resolution ΔE < 1 meV.
John Barrett - One of the best experts on this subject based on the ideXlab platform.
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Digital spectral analysis of the drill-bone acoustic interface during temporal bone dissection: a qualitative cadaveric pilot study.
Otology & Neurotology, 2006Co-Authors: Neville Patrick Shine, Joseph Connell, Peter O'sullivan, PAWEL RULIKOWSKI, John BarrettAbstract:HYPOTHESIS: To qualitatively assess the different acoustic signatures of an otologic drill burr-bone interface during temporal bone dissection on full thickness calvarial and thin tegmen bone. BACKGROUND: An appreciable change in the sound generated by drilling occurs with progressive thinning of the bone during temporal bone dissection. To date, descriptions of this phenomenon are limited to a handful of subjective characterizations. Using digital power spectral analysis, interpretation of complex functions of time such as acoustic signals can be interpreted. METHODS: Acoustic data recorded from five cadaveric temporal bone dissections were studied using digital spectral analysis. RESULTS: The Energy Bandwidth concentration was between 5.0 and 7.9 kHz for full thickness bone using the cutting burr. Thin tegmen bone Bandwidth concentration was lower, between 3.7 and 7.4 kHz and 3.9 and 6.0 kHz, using cutting and diamond burrs, respectively. Harmonic frequencies for thin tegmen bone-burr signals were 630 Hz. CONCLUSION: There is a consistent, reproducible qualitative difference in the spectral domain of the acoustic signature from the drill burr-bone interface between thick calvarial bone and thin tegmen bone caused by a higher harmonic peak interval and lower Energy Bandwidth concentration in the thinned tegmen bone-burr interface signal thus concentrating the acoustic signal within a more optimal frequency range for human perception. These results allow for a better understanding of the perceived change in sound with progressive thinning of bone with drilling. In addition, these data may allow the development of more realistic acoustic interfaces in virtual reality temporal bone dissection simulators.
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Digital spectral analysis of the drill-bone acoustic interface during temporal bone dissection: a qualitative cadaveric pilot study.
Otology & Neurotology, 2006Co-Authors: Neville Patrick Shine, Joseph Connell, Peter O'sullivan, PAWEL RULIKOWSKI, John BarrettAbstract:HYPOTHESIS: To qualitatively assess the different acoustic signatures of an otologic drill burr-bone interface during temporal bone dissection on full thickness calvarial and thin tegmen bone. BACKGROUND: An appreciable change in the sound generated by drilling occurs with progressive thinning of the bone during temporal bone dissection. To date, descriptions of this phenomenon are limited to a handful of subjective characterizations. Using digital power spectral analysis, interpretation of complex functions of time such as acoustic signals can be interpreted. METHODS: Acoustic data recorded from five cadaveric temporal bone dissections were studied using digital spectral analysis. RESULTS: The Energy Bandwidth concentration was between 5.0 and 7.9 kHz for full thickness bone using the cutting burr. Thin tegmen bone Bandwidth concentration was lower, between 3.7 and 7.4 kHz and 3.9 and 6.0 kHz, using cutting and diamond burrs, respectively. Harmonic frequencies for thin tegmen bone-burr signals were 630 Hz. CONCLUSION: There is a consistent, reproducible qualitative difference in the spectral domain of the acoustic signature from the drill burr-bone interface between thick calvarial bone and thin tegmen bone caused by a higher harmonic peak interval and lower Energy Bandwidth concentration in the thinned tegmen bone-burr interface signal thus concentrating the acoustic signal within a more optimal frequency range for human perception. These results allow for a better understanding of the perceived change in sound with progressive thinning of bone with drilling. In addition, these data may allow the development of more realistic acoustic interfaces in virtual reality temporal bone dissection simulators.